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Richard York teaches sociology at the University of Oregon. His research interests include the global environmental crisis and the philosophy, history, and sociology of science. He is coeditor of the Sage journal Organization & Environment. Brett Clark recently received his PhD from the University of Oregon. His research focuses on ecological crisis, political economy, and science.

In The Second Sex, Simone de Beauvoir noted that “legislators, priests, philosophers, writers, and scientists have striven to show that the subordinate position of woman is willed in heaven” making use “of philosophy and theology.” When the ordained order from above fails as justification for explaining earthly relations, she pointed out, “antifeminists” draw upon “science—biology, experimental psychology, etc.”—as the means to naturalize inequalities. When challenged, they will claim that there is “‘equality of difference’ to the other sex”—innate differences in ability, but moral equality: the same formula that was used to justify racial discrimination through Jim Crow laws in the United States. This “equal but separate” logic, de Beauvoir contended, follows other forms of discrimination, “whether it is a race, a caste, a class, or a sex that is reduced to a position of inferiority, the methods of justification are the same.” Social inequalities and this ideology make it difficult “to realize the extreme importance of social discriminations which seem outwardly insignificant but which produce in woman moral and intellectual effects so profound that they appear to spring from her original nature.” In order to overcome social inequalities between the sexes, she stressed, a critique of both the concrete conditions and the ideology that limit women’s liberty is necessary.1

Notoriously, in a speech delivered on January 14, 2005, at a conference focused on diversifying the science and engineering workforce, Lawrence Summers, then president of Harvard University, suggested that the over-representation of men in science and engineering in tenured positions at the elite universities and research institutions may be in partdue to innate differences in ability between the sexes, reigniting debate about the relationship between biological characteristics and social position. The persistent difference in representation of men and women in these fields, he posited, is the result of “the general clash between people’s legitimate family desires and employers’ current desire for high power and high intensity, that in the special case of science and engineering, there are issues of intrinsic aptitude, and particularly of the variability of aptitude, and that those considerations are reinforced by what are in fact lesser factors involving socialization and continuing discrimination.”2

Summers, of course, is not known for his support of social justice. Among other things, he infamously issued a memorandum in 1991, while chief economist at the World Bank, suggesting that wealthy nations should export pollution to poor nations, since, as he put it, “the economic logic behind dumping a load of toxic waste in the lowest-wage country is impeccable and we should face up to that.” He was later secretary of treasury in the Clinton administration, before being appointed president of Harvard. While at Harvard, Summers attacked African-American Studies professor Cornel West for his political activism. As a representative of mainstream economics, Summers’s comments regarding sex and science are not particularly surprising in themselves. But the fact that they articulate a belief that is widely held, and that the president of a leading educational institution and former cabinet member in a Democratic administration felt called to voice them so publicly, suggests that the controversy over purported sex differences in scientific ability cannot be ignored.

Following his comments, Summers was widely criticized, but several prominent scholars nevertheless weighed-in in favor of his views. For example, MIT cognitive psychologist Steven Pinker and Cambridge biologist Peter Lawrence both endorsed the view that even if gender discrimination was completely ended, men would still outnumber women in the physical sciences due to innate sex-based differences.3 Both Pinker and Lawrence recognize the historical role of gender discrimination in creating inequalities in universities and society and support policies to address such conditions. However, their arguments in support of innate sex-based differences center on claims that men are better at mathematical problem solving and spatial visualization, while women are superior at mathematical calculation. These differences, it is contended, in part, explain the under-representation of women in science and engineering.

Biological justifications for gender inequality have of course been a mainstay of modern supporters of sociobiology and its more recent descendant evolutionary psychology. For example, in the same year he published his influential book Sociobiology, the Harvard biologist Edward O. Wilson argued for a biological predisposition for the gendered division of labor:

In hunter-gatherer societies, men hunt and women stay at home. This strong bias persists in most agricultural and industrial societies and, on that ground alone, appears to have a genetic origin….My own guess is that the genetic bias is intense enough to cause a substantial division of labor even in the most free and most egalitarian of future societies…. Even with identical education and equal access to all professions, men are likely to continue to play a disproportionate role in political life, business and science.4

Such essentialist views are hardly new even if arrayed in fashionable clothing. The argument that social inequalities are a reflection of an immutable natural order predates the formalization of sociobiology in the latter part of the twentieth century. As the late Harvard paleontologist Stephen Jay Gould has noted, “[R]esurgences of biological determinism correlate with episodes of political retrenchment, particularly with campaigns for reduced government spending on social programs.”5 Given that we are in a period of political retrenchment, it should be no surprise that those in power invoke biology as a justification of social inequality and that this invocation receives considerable public attention. Hence it remains as important as ever to assess the scientific evidence for and the real consequences of biological explanations of social inequality.

Richard Lewontin and Richard Levins expound that the prevailing scientific approach to “biology…plays a central role in creating an ideology of the inevitability of the structure of society” and its social relations.6 Gender inequalities are determined to be “the consequence of unequal distributions of temperament, skill and cognitive power, manifestations of genetically determined differences between individuals, races and the sexes.” These attempts to naturalize differences between men and women as expressions of “essentially biological sex differences” via scientific claims “represent a systematic selection, misrepresentation, or improper extrapolation of the evidence, larded with prejudice and basted in poor theory, and…far from accounting for present divisions, they serve as ideologies that help perpetuate them.”7 Such biological determinism veils the long history of social inequalities that contribute to contemporary social relations and differences between the sexes.

A 2007 report, Behind the Pay Gap, by Judy Goldberg Dey and Catherine Hill, indicates that women have slightly higher grade point averages than men in colleges and universities in every major, including math and science. Nonetheless, women one year after college, working full time, receive approximately 80 percent of the income of their male counterparts. The pay gap between men and women increases through the years: “Ten years after graduation, women working full time earn only 69 percent as much as men working full time earn.”8 Even within female-dominated occupations, the gender pay gap persists. Dey and Hill point out that even accounting for such things as different gender choices and characteristics does not explain pay disparity between men and women.

With regard to the representation of women in the physical sciences and mathematics, there is certainly something to be explained. Among the top fifty departments in the United States (from 2001 to 2003), women received only 25 percent of the PhDs in the physical sciences and mathematics and 15 percent of the PhDs in engineering. More extreme than this, in these same departments, only 6 percent of full professors in the physical sciences and 4 percent in engineering are women.9 The question is not whether there is gender inequality in the sciences—there clearly is—but rather whether this inequality stems from differences in innate ability or the operation of our social institutions. This question is all the more important, given that assumptions are made in regards to intrinsic abilities of men and women based upon a social determination that science and engineering represent the pinnacle of human intellect.

Our aim here is to evaluate the scientific claims used to justify inequality via biological determinist arguments, particularly with regard to the underrepresentation of women in mathematics and the physical sciences, and to consider the consequences of those claims. Although we do not condemn questions about biologically based differences across human groups—be they genders, races, or other categorizations—as illegitimate as a topic of scientific inquiry, we do question why the search for such differences receives considerable political support and media attention and why the finding of any minuscule, tenuous, and therefore dubious “difference” is so readily held up as a cause (rather than effect) of social inequality. Furthermore, we do not assert that those who espouse biological deterministic views are intentionally acting to further oppression—indeed, we accept that many of those holding such views are sincere and believe in fair and equal treatment of individuals—but we believe it is important to critique the social and political context that fosters and disseminates such views. The acceptance of the view that men are innately superior to women in math and science is remarkably widespread, despite the questionable nature of most evidence supporting such a position. Of course, the problem with widespread belief in innate differences in intellectual abilities of a more than trivial magnitude across the sexes is not simply that it is almost surely false, but that it serves to reproduce the inequalities it purports to explain.

Despite the attention paid to claims of substantial differences in various types of abilities—including mathematical, spatial, and verbal—between the sexes, it is remarkable that most research finds these differences to be trivial or small (even assuming that they can be measured properly and that all intervening factors can be accounted for).10 For example, using large national datasets on mathematical performance among children in the United States, sociologists Erin Leahey and Guang Guo found that there was only “a slight, late-emerging male advantage in mathematics among the general population of students,” with “no male advantage until later in high school, where the largest gender difference is 1.5%.”11 Furthermore, they did not even find large differences among high-scoring students, where it is commonly assumed that males will be most dominant. Using meta-analysis of existing research, psychologist Janet Shibley Hyde and her colleagues have found that not only are differences in mathematical performance across genders typically small, they have generally decreased over time (indicating that they are mutable), often favor women, particularly at younger ages, and that the gender that scores higher differs across ethnic groups.12 Furthermore, research shows that differences in mathematical performance among children across nations dwarf gender differences within nations.13 These types of findings have led Hyde to propose the “gender similarities hypothesis,” which holds that men and women are similar on most psychological variables, counter to the widespread, but largely unsupported, assumption that there are substantial gender differences.14

In light of these research findings, it appears that the existence of significant differences in mathematical performance across genders has not even been established. Furthermore, to the extent that differences have been demonstrated, they have not been compellingly shown to be innate or inevitable. Differences in abilities between the sexes may well be due simply to disparities in opportunities, socialization, and other environmental forces that are potentially mutable in their entirety. The measured differences in ability within genders far exceed differences between them. Given the lack of support for the existence of substantial differences in mathematical ability between men and women, it seems implausible to claim that the striking gender imbalance in science departments in the academy is principally a reflection of sex-based biological differences—an assumption all the more implausible given the still very wide social divisions separating the sexes in today’s society.

One problem with the uncritical acceptance of biological explanations of gender inequalities is, of course, that it can undermine efforts to end discrimination and improve opportunities for all people. Another less appreciated problem is that the prevalence of biological determinist views on gender and mathematical ability can actually lead directly to the under-performance of women in mathematics, as has been demonstrated experimentally by psychologists at the University of British Columbia.15 Ilan Dar-Nimrod and Steven J. Heine performed an experiment where over a hundred female university students who were screened for mathematical proficiency were randomly assigned to four test conditions, taking a Graduate Record Exam-like test, without knowing the purpose of the study. In all test conditions, there were two math sections separated by a verbal section. The verbal section contained a reading comprehension essay, the subject of which was the focus of the experimental manipulation. Of the four test conditions, in one (1) the essay asserted that sex differences in math performance were due to genetics; in another (2) that the differences were because of teachers biased expectations during formative years, an experiential explanation; in yet another (3) that there are no math-related gender differences; and, finally, another (4) did not mention math, but primed the topic of sex by discussing women’s identity. Of the four groups of subjects, those experiencing test conditions 2 and 3 performed effectively the same as one another on the second test, but performed on average significantly better than did those experiencing test conditions 1 and 4 (which did not differ significantly in their performance from one another).

The results point to the conclusion that emphasizing either that there is no difference between the sexes or that differences are due to experiential causes, rather than genetic ones, can lead to better mathematical performance in women. The similar performance of those subjected to the genetic explanation and those that were primed on the topic of sex without presenting the sex-related stereotype about math performance led the researchers to suggest that “People appear to habitually think of some sex differences in genetic terms unless they are explicitly provided with experiential arguments.” They further concluded that, “These findings raise discomforting questions regarding the effects that scientific theories can have on those who learn about them and the obligation that scientists have to be mindful of how their work is interpreted.” The persistence of a gender “stereotype threat”—in combination with other social barriers—could “exacerbate the gender gap in science.”

There is a long and tragic history of justifying inequality via the invocation of supposedly objective, value-free research, which in hindsight can be recognized as fundamentally flawed.16 Stanford neurobiologist Ben Barres articulates the concern about the toll of biological determinism and the responsibility of scholars particularly well: “It is incumbent upon those proclaiming gender differences in abilities to rigorously address whether suspected differences are real before suggesting that a whole group of people is innately wired to fail.”17 The evidence indicates that there are clear negative consequences that can be created as a result of actively promoting the argument for innate gender differences in abilities.

Certainly individual human beings differ in behavior, and these differences are related to the biology of each individual, but as Richard Lewontin, Steven Rose, and Leon Kamin explain “the determinants of behavior are irredeemably interactive and ontogenetic.” Individuals—including their capabilities and potentials—are influenced by their biology, culture, environment, and history. We cannot “divide behavior chronologically into a portion given by biology and another given by culture.” We must avoid the “reductionist trap” that assumes that “biological difference is primary and causative of the ‘higher level’ psychological one; both are different aspects of the same unitary phenomenon.”18 Our social history and biology both constrain and enable human beings. “But the division of causality between distinct biological and social causes which then may interact misses the real nature of their codetermination.” Rather than being constrained by a few internal, innate causes, human beings are able to employ their “brains, hands, and tongues” to recreate themselves and the natural world. Our biology, in part, has provided the means through which humans make history within the historical-structural conditions (natural and social) of the present, but it does not determine social outcomes.19 In order to enhance the potential of all people to excel, we must address the socio-historical conditions that influence social inequalities and struggle against these conditions to forge the path for a new social order.

The recent and sharp rise in the social achievement of women in U.S. society clearly belies claims that gender inequalities are immutable. For example, between 1970 and 2004, the percentage of physicians who are women rose more than three-fold, from 7.6 percent to 26.6 percent. Likewise, in a few years, from 1994 to 2002, the percentage of lawyers who are women rose from 23 percent to over 29 percent.20 Although these statistics show that we are still a long way from gender equality in medicine and law, they also clearly demonstrate that social inequalities can change dramatically in a short space of time. Rather than assuming little can be done to reduce gaps between men and women, it would be more productive and more just to work to narrow these gaps.

Our point here has been to argue that, despite common perceptions to the contrary, the evidence in support of sex-based differences in math performance is surprisingly weak, does not convincingly show that any differences are genetic in origin, and that perpetuating biologically deterministic views can actually generate differences in performance. We are not suggesting that it should be taboo to ask questions about innate differences across human groups—we fully support the right of scholars to free inquiry. However, we also think that it is important to be particularly skeptical when scientific findings fit all too comfortably with prevailing social prejudices and the interests of dominant social groups, especially if they are put forward at the expense of addressing important social barriers. Insightfully, de Beauvoir indicated that as long as “woman is the Other” all justifications of inequalities should be cast under suspicion.21